1. Field of the Invention
The present invention relates to an optical device capable of arbitrarily varying the optical properties of passing light beam by varying, the relative angle, or vertical angle, of two transparent parallel-faced flat plates enclosing an optically transparent material therein, adapted for use, for example, in a vibration-compensating optical system to be positioned in a part of the phototaking system of a photographic camera, a video camera or the like for compensating the image shaking, resulting from vibration of said phototaking system, and a producing method therefor.
2. Related Background Art
There are already proposed various optical devices composed of two transparent parallel-faced flat plates enclosing, therebetween an optical transparent material such as liquid or silicone rubber, thereby constituting a prism member with variable vertical angle, and capable of arbitrarily varying the optical properties of the passing light beam by varying the relative angle of said two plates by an external biasing force.
For example, FIGS. 64 and 65 are schematic views of an optical device proposed in the Japanese Patent Publication Sho 41-11906. Said optical device is composed of two transparent parallel-faced flat plates 201, 201' positioned in mutually opposed relationship, supported along the periphery by a flexible connecting member 202 and enclosing transparent liquid 203 therein, thereby deflecting an incident light beam h by a certain angle.
FIGS. 66 and 67 are schematic views of an optical device proposed in the Japanese Laid-open application sho 60-176017. Said optical device is composed of two transparent parallel-faced flat plates 221, 221' positioned in mutually opposed relationship and sandwiching a transparent elastic member 224 therebetween, serving to deflect an incident light beam by a certain angle as in the case of FIG. 64. Such conventional optical devices constitute a prism with variable vertical angle, wherein the vertical angle can be arbitrarily controlled by varying the relative angle of two flat plates by an external biasing force as shown in FIGS. 65 and 67.
However, in such conventional optical devices, the change in the angle of two flat plates is achieved by expansion or contraction of a connecting member of a certain material and generally requires a large driving force, requiring a large driving source. Also repeated deformations may result in a partial breakage of the connecting member.
Furthermore, such devices have been associated with drawbacks that the material supported between two flat plates penetrates the connecting member or oozes through the junction between the connecting member and the flat plate, or that the transparent elastic member results in a change in the refractive index by moisture absorption from the air.
Also the adhered portions between the connecting member and the flat plates is subjected to an external force in the drive of the optical device, eventually leading to peeling of the adhered portions and oozing of the internal material.
Furthermore such conventional devices cannot be compactized sufficiently, because the paired parallel-faced flat plates and the supporting member are same in dimension and/or shape.